Problem pointing to structure members

[Fortean Jo]

I have a simple string copy procedure along the lines of:

     Str_copy     proc  src_str: PTR, dest_str: PTR
            ..
           copy code
            ..
     Str_copy    endp

I also have some string variables defined as follows:

    Str1           db  256 (?)
    Str2           db  128 (?)

I can use my str copy routine like so:

   Str_copy, offset Str1, offset Str2

and everything works fine.  However, I have a structure with various members, including strings, like so:

   MyStruc     STRUC
       Str_Len       dd   ?
       Struc_Str     db  256 (?)
   MyStruc    ends

   My_Struc_Ptr    dd  0

This structure is allocated on the heap via LocalAlloc and is addressed via My_Struc_Ptr

However, whenever I try to copy to Struc_Str, I get an error.  My code is like this:

    invoke  LocalAlloc, LMEM_FIXED, SizeOf My_Struc
    mov     My_Struc_Ptr, eax

and further on

   mov     esi, My_Struc_Ptr
   invoke  Str_copy, Str1, (My_Struc PTR [esi]).Struc_Str

This causes an assembly error since Str_copy is expecting 2 pointers.

The question is, then, how do I address [esi].Struc_Str as a pointer?

[Mirno]

Have you tried:

Code Select Expand


   invoke  Str_copy, Str1, ADDR (My_Struc PTR [esi]).Struc_Str


ADDR is like OFFSET, but can do more complicated stuff. It only works in an invoke statement though, and may generate additional code if it needs to (like an lea instruction).

Mirno

[Fortean Jo]

That's what I'm looking for - works perfect.  :bg

Cheers  :U

[P1]

Please remember for structures or data types that may have nulls, you need to do your copy based on length.

Regards,  P1  :8)